I'm wondering why you are even using these products? Do you have a high-tech planted tank (using CO2 diffusion, high light, heavy ferts)?

Aside from the above situation, using individual products can be very detrimental not only to the plants but the fish. Iron is a heavy metal and highly toxic to all fish and plant life at levels above the minimum required as nutrient. I can comment further if asked, but this is not something I would risk in my aquaria.

The aquarist is one who must learn the ways of the biologist, the chemist, and the veterinarian.[unknown source]

Something we all need to remember: The fish you've acquired was quite happy not being owned by you, minding its own business. If you’re going to take it under your wing then you’re responsible for it. Every aspect of its life is under your control, from water quality and temperature to swimming space. [Nathan Hill in PFK]